KVM: arm64: Simplify __kvm_hyp_init HVC detection

The arguments for __do_hyp_init are now passed with a pointer to a
struct which means there are scratch registers available for use. Thanks
to this, we no longer need to use clever, but hard to read, tricks that
avoid the need for scratch registers when checking for the
__kvm_hyp_init HVC.

Tested-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210125145415.122439-2-ascull@google.com
This commit is contained in:
Andrew Scull 2021-01-25 14:54:14 +00:00 committed by Marc Zyngier
parent 19c329f680
commit 87b26801f0
1 changed files with 3 additions and 10 deletions

View File

@ -55,17 +55,10 @@ __do_hyp_init:
cmp x0, #HVC_STUB_HCALL_NR
b.lo __kvm_handle_stub_hvc
// We only actively check bits [24:31], and everything
// else has to be zero, which we check at build time.
#if (KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) & 0xFFFFFFFF00FFFFFF)
#error Unexpected __KVM_HOST_SMCCC_FUNC___kvm_hyp_init value
#endif
mov x3, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init)
cmp x0, x3
b.eq 1f
ror x0, x0, #24
eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 24) & 0xF)
ror x0, x0, #4
eor x0, x0, #((KVM_HOST_SMCCC_FUNC(__kvm_hyp_init) >> 28) & 0xF)
cbz x0, 1f
mov x0, #SMCCC_RET_NOT_SUPPORTED
eret